The examples in the subsequent sections illustrate the
following aspects of PHP for SCA:

How PHP annotations are used to define PHP classes as SCA
components, and how annotations are used to define the
services.

How an SCA component can be exposed as a Web service

How an SCA component can consume a Web service, whether
provided by another SCA component or by some other service which
knows nothing of SCA

How an SCA component can call another SCA component locally
(within the same process and on the same call stack)

How a client script which is not an SCA component can use the
getService call to obtain a proxy for an SCA component.

How data structures such as Addresses, or Puchase Orders,
are represented as Service Data Objects, and handled.

How SCA components are deployed, and in particular how and
when WSDL is generated for a service.

How parameters are always passed by value (and not by
reference) between components, even when the calls are local.
This ensures that the semantics of a call do not change depending on
the location of a component.

How positional parameters to a service are supported, even
when the underlying WSDL is document literal wrapped, and
naturally supports only named parameters.